Ferns for Terrariums: The Best Varieties for Beginners
Ferns and terrariums are a natural pairing. Most ferns evolved in the shaded, humid understory of forests, which is almost exactly the environment a well-built terrarium recreates in miniature. That said, some ferns are considerably easier to start with than others, particularly if you're building your first closed or semi-closed container.
Boston fern
One of the most widely grown houseplant ferns, and for good reason: it tolerates a fairly wide range of humidity, which makes it forgiving while a new terrarium's conditions stabilise. Its fronds arch outward in a full, feathery shape, so it works well as a taller centerpiece plant rather than tucked into a corner. It does need reasonably frequent watering compared with some of the plants on this list, so it's better suited to an open terrarium or a closed one you check on regularly.
Maidenhair fern
Prized for its delicate, almost lacy fronds on thin dark stems, maidenhair fern is more particular about consistent humidity than the Boston fern, and dry air will brown its fronds quickly. That pickiness is exactly why it's such a good closed-terrarium plant — the stable, high humidity behind a sealed lid is precisely what it wants, and it rewards that consistency with some of the most delicate foliage of any common terrarium plant.
Bird's nest fern
Instead of the classic feathery fronds, bird's nest fern grows broad, wavy-edged leaves in a rosette shape, giving a terrarium a very different texture from the other plants on this list. It's an epiphyte in the wild, often growing on trees rather than in soil, which makes it naturally tolerant of the free-draining substrate a terrarium needs. It handles a range of humidity reasonably well, making it a flexible choice for either open or closed builds.
Table fern
A compact, upright fern that stays relatively small and tidy, table fern is a good choice when floor space is limited — a small jar or narrow-necked vessel that can't accommodate a wide, arching Boston fern can often still fit a table fern comfortably. It appreciates the same humid, indirect-light conditions as most terrarium ferns and doesn't ask for much beyond that.
General care that applies to all of them
Every fern on this list shares a few preferences: bright, indirect light rather than direct sun (which will scorch fronds fast behind glass), consistently moist but not waterlogged substrate, and still, humid air. None of them are picky about soil pH or fertiliser in a terrarium setting — a standard terrarium or fern-specific potting mix suits all four.
Where they differ most is tolerance for lower humidity and less frequent attention. If you're building an open terrarium you'll check often, Boston fern and bird's nest fern are the more forgiving starting points. If you're building a sealed jar you'd rather leave mostly alone, maidenhair fern will reward the stable humidity with its finest, most delicate growth.
Keeping a fern in bounds
All four of these ferns will eventually grow past the size they arrived at, and a terrarium is a fixed space, so a little grooming keeps things in proportion. Snipping off a browning or damaged frond at its base, rather than partway along the stem, keeps the plant looking tidy without leaving a stub behind. If a fern's root ball genuinely outgrows the space it was given, dividing it and replanting a smaller section is usually more successful than trying to squeeze the whole original plant into an unchanged footprint.
Whichever fern you choose, it's worth working out how many will comfortably fit your container before you buy, since ferns' fronds spread out considerably wider than the small starter plant you bring home. The plant count calculator on this site estimates how many will fit your floor area at a sparse, moderate, or full planting density based on the plant's mature spread.